Trimethyl-lysine

The phenylselenocysteine has also been used successfully to chemically append analogues of methyl- or acetyl-lysine, important histone modifications that can contribute to chromatin structure and accessibility of transcriptional machinery in eukaryotes. By introducing phenylselenocysteine into the Xenopus histone H3, both acetyl-lysine and mono-, di-, and trimethyl-lysine analogues were appended to the purified unnatural amino acid-containing FI 3 protein (Figure 10). " Additionally, the H3 protein with a modification mimicking acetylation of lysine 9 can be deactylated by a histone deacetylation complex and is also a substrate for phosphorylation by Aurora B kinase. Such purified and chemically labeled histones are likely functional in nucleosomes, and preparation of specifically modified histones for comprehensive analysis of chromatin structure and accessibility is particularly suited to this chemical labeling technique. 

Trimethyl lysine hydroxylase Hydroxylation of trimethyl lysine Carnitine synthesis... 

In addition to collagen metabolism and scavenging ROS species to limit inflammation as noted above, ascorbate is required for the synthesis of norepinephrine from tyrosine, of carnitine from y-butyrobetaine whose immediate precursor is made by trimethylating lysine, for folinic acid production from folic acid. In the absence of ascorbate, the reduced activity of these processes slows nerve, energy and cardiac output, causingthe affected person to become exhausted and irritable. Scurvy is the old English word for ill-tempered. 

Lysine is converted into carnitine through a chain reaction driven at two points by dioxygenases (or hydroxylases) that act on y-butyrobe-taine and trimethyl-lysine and that require vitamin C for full activity. Carnitine is essential for the transport of energy-rich fatty acids from the cytoplasm to the mitochondrial matrix where they are catabolised by jS-oxidation to acetate. 

M. Esteller, Loss of acetylated lysine 16 and trimethylated lysine 20 of histone H4 is a common hallmark of human cancer, Nat. Genet. 2005, 37, 391-400. 

LaBadie, J., W.A. Dunn, and N.N. Jr. Aronson. 1976. Hepatic synthesis of carnitine from protein-bound trimethyl-lysine. Lysosomal digestion of methyl-lysine-labelled asialo-... 

LaBadie, J. Dunn, W.A. Aronson, N.N. Jr. Hepatic Synthesis of Carnitine from Protein-Bound Trimethyl-Lysine. Lysosomal Digestion of Methyl-Lysine-Labelled Asialo-Fetuin. Bio-chem. J. 1976, 160, 85-95. 

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